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鸿蒙5蓝牙防丢器应用开发指南 原创
进修的泡芙
发布于 2025-6-20 14:33
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鸿蒙5蓝牙防丢器应用开发指南
一、项目概述
本文基于HarmonyOS 5的蓝牙近距离感知能力和分布式技术，开发一款蓝牙防丢器应用，借鉴《鸿蒙跨端U同步》中游戏多设备同步的技术原理，实现设备间的距离监测、分离报警和多设备协同定位功能。该系统能够在绑定设备超出安全距离时触发报警，并通过分布式能力实现多设备间的状态同步。
二、系统架构
±--------------------+ ±--------------------+ ±--------------------+
主控手机设备 <-----> 分布式数据总线 <-----> 蓝牙防丢器设备
(Master Phone) (Distributed Bus) (Bluetooth Tracker)
±---------±---------+ ±---------±---------+ ±---------±---------+
±---------v----------+ ±---------v----------+ ±---------v----------+
报警逻辑引擎 状态同步服务 距离监测模块
(Alert Engine) (Sync Service) (Distance Monitor)
±--------------------+ ±--------------------+ ±--------------------+
三、核心代码实现
设备数据模型
// src/main/ets/model/TrackerDeviceModel.ts
export class TrackerDevice {
deviceId: string; // 设备唯一标识
name: string; // 设备名称
lastConnected: number; // 最后连接时间
lastRssi: number; // 最后信号强度
safeDistance: number; // 安全距离(米)
isConnected: boolean; // 是否连接
isAlerting: boolean; // 是否正在报警
batteryLevel: number; // 电池电量(0-100)
position?: { // 最后已知位置(可选)
latitude: number;
longitude: number;
};
constructor(deviceId: string, name: string) {
this.deviceId = deviceId;
this.name = name;
this.lastConnected = Date.now();
this.lastRssi = 0;
this.safeDistance = 10;
this.isConnected = false;
this.isAlerting = false;
this.batteryLevel = 100;
updateRssi(rssi: number): void {
this.lastRssi = rssi;
this.lastConnected = Date.now();
calculateDistance(): number {
// 根据RSSI估算距离(简化版)
if (this.lastRssi >= 0) return Infinity;
const txPower = -59; // 1米处的RSSI值
return Math.pow(10, (txPower - this.lastRssi) / (10 * 2));
toJson(): string {
return JSON.stringify({
deviceId: this.deviceId,
name: this.name,
lastConnected: this.lastConnected,
lastRssi: this.lastRssi,
safeDistance: this.safeDistance,
isConnected: this.isConnected,
isAlerting: this.isAlerting,
batteryLevel: this.batteryLevel,
position: this.position
});
static fromJson(jsonStr: string): TrackerDevice {
const json = JSON.parse(jsonStr);
const device = new TrackerDevice(json.deviceId, json.name);
device.lastConnected = json.lastConnected;
device.lastRssi = json.lastRssi;
device.safeDistance = json.safeDistance;
device.isConnected = json.isConnected;
device.isAlerting = json.isAlerting;
device.batteryLevel = json.batteryLevel;
device.position = json.position;
return device;
}
分布式同步服务
// src/main/ets/service/DistributedSyncService.ts
import { distributedData } from ‘@ohos.data.distributedData’;
import { BusinessError } from ‘@ohos.base’;
import { TrackerDevice } from ‘…/model/TrackerDeviceModel’;
import { deviceManager } from ‘@ohos.distributedDeviceManager’;
export class DistributedSyncService {
private static instance: DistributedSyncService;
private kvManager: distributedData.KVManager;
private kvStore: distributedData.KVStore;
private readonly STORE_ID = ‘tracker_store’;
private readonly DEVICE_KEY_PREFIX = ‘tracker_’;
private subscribers: ((data: TrackerDevice) => void)[] = [];
private constructor() {
this.initDistributedData();
public static getInstance(): DistributedSyncService {
if (!DistributedSyncService.instance) {
DistributedSyncService.instance = new DistributedSyncService();
return DistributedSyncService.instance;
private initDistributedData(): void {
const config: distributedData.KVManagerConfig = {
bundleName: 'com.example.tracker',
userInfo: {
userId: '0',
userType: distributedData.UserType.SAME_USER_ID
};
try {
distributedData.createKVManager(config, (err: BusinessError, manager: distributedData.KVManager) => {
if (err) {
console.error(Failed to create KVManager. Code: {err.code}, message: {err.message});
return;
this.kvManager = manager;
const options: distributedData.Options = {
createIfMissing: true,
encrypt: true,
backup: false,
autoSync: true,
kvStoreType: distributedData.KVStoreType.SINGLE_VERSION,
schema: '',
securityLevel: distributedData.SecurityLevel.S2
};
this.kvManager.getKVStore(this.STORE_ID, options, (err: BusinessError, store: distributedData.KVStore) => {
if (err) {
console.error(Failed to get KVStore. Code: {err.code}, message: {err.message});
return;
this.kvStore = store;
this.registerDataListener();
});
});
catch (e) {
console.error(An unexpected error occurred. Code: {e.code}, message: {e.message});
}
private registerDataListener(): void {
try {
this.kvStore.on(‘dataChange’, distributedData.SubscribeType.SUBSCRIBE_TYPE_ALL, (data: distributedData.ChangeData) => {
if (data.key.startsWith(this.DEVICE_KEY_PREFIX)) {
const device = TrackerDevice.fromJson(data.value.value as string);
this.notifySubscribers(device);
});
catch (e) {
console.error(Failed to register data listener. Code: {e.code}, message: {e.message});
}
public subscribe(callback: (data: TrackerDevice) => void): void {
this.subscribers.push(callback);
public unsubscribe(callback: (data: TrackerDevice) => void): void {
this.subscribers = this.subscribers.filter(sub => sub !== callback);
private notifySubscribers(data: TrackerDevice): void {
this.subscribers.forEach(callback => callback(data));
public syncDevice(device: TrackerDevice): void {
if (!this.kvStore) {
console.error('KVStore is not initialized');
return;
try {
const key = this.DEVICE_KEY_PREFIX + device.deviceId;
this.kvStore.put(key, device.toJson(), (err: BusinessError) => {
if (err) {
console.error(Failed to put device. Code: {err.code}, message: {err.message});
});
catch (e) {
console.error(An unexpected error occurred. Code: {e.code}, message: {e.message});
}
public async getTrackedDevices(): Promise<TrackerDevice[]> {
return new Promise((resolve) => {
if (!this.kvStore) {
resolve([]);
return;
try {
const query: distributedData.Query = {
prefixKey: this.DEVICE_KEY_PREFIX
};
this.kvStore.getEntries(query, (err: BusinessError, entries: distributedData.Entry[]) => {
if (err) {
console.error(Failed to get entries. Code: {err.code}, message: {err.message});
resolve([]);
return;
const devices = entries.map(entry =>
TrackerDevice.fromJson(entry.value.value as string)
);
resolve(devices);
});
catch (e) {
console.error(An unexpected error occurred. Code: {e.code}, message: {e.message});
resolve([]);
});
}
蓝牙距离监测服务
// src/main/ets/service/BluetoothTrackerService.ts
import { bluetooth } from ‘@ohos.bluetooth’;
import { BusinessError } from ‘@ohos.base’;
import { TrackerDevice } from ‘…/model/TrackerDeviceModel’;
import { DistributedSyncService } from ‘./DistributedSyncService’;
import { geolocation } from ‘@ohos.geolocation’;
export class BluetoothTrackerService {
private static instance: BluetoothTrackerService;
private syncService = DistributedSyncService.getInstance();
private trackedDevices: Map<string, TrackerDevice> = new Map();
private scanInterval: number = 0;
private alertTimeout: number = 0;
private constructor() {
this.initBluetooth();
public static getInstance(): BluetoothTrackerService {
if (!BluetoothTrackerService.instance) {
BluetoothTrackerService.instance = new BluetoothTrackerService();
return BluetoothTrackerService.instance;
private initBluetooth(): void {
try {
bluetooth.enableBluetooth();
bluetooth.on('bluetoothStateChange', (state: number) => {
console.log(Bluetooth state changed: ${state});
});
bluetooth.on('deviceFind', (device: bluetooth.BluetoothDevice) => {
if (this.trackedDevices.has(device.deviceId)) {
this.updateDeviceRssi(device.deviceId, device.rssi);
});
catch (e) {
console.error(Failed to init Bluetooth. Code: {e.code}, message: {e.message});
}
public startTracking(device: TrackerDevice, interval: number = 5000): void {
this.trackedDevices.set(device.deviceId, device);
this.syncService.syncDevice(device);
if (!this.scanInterval) {
this.scanInterval = setInterval(() => {
this.performScan();
}, interval);
}
public stopTracking(deviceId: string): void {
this.trackedDevices.delete(deviceId);
if (this.trackedDevices.size === 0 && this.scanInterval) {
clearInterval(this.scanInterval);
this.scanInterval = 0;
}
private performScan(): void {
try {
bluetooth.startBluetoothDiscovery();
// 10秒后停止扫描
setTimeout(() => {
bluetooth.stopBluetoothDiscovery();
this.checkDevicesDistance();
}, 10000);
catch (e) {
console.error(Failed to perform scan. Code: {e.code}, message: {e.message});
}
private updateDeviceRssi(deviceId: string, rssi: number): void {
const device = this.trackedDevices.get(deviceId);
if (device) {
device.updateRssi(rssi);
device.isConnected = true;
this.syncService.syncDevice(device);
}
private async checkDevicesDistance(): Promise<void> {
for (const [deviceId, device] of this.trackedDevices) {
const distance = device.calculateDistance();
if (distance > device.safeDistance) {
device.isAlerting = true;
this.triggerAlert(device);
else {
device.isAlerting = false;
// 更新设备位置
await this.updateDevicePosition(device);
this.syncService.syncDevice(device);
}
private async updateDevicePosition(device: TrackerDevice): Promise<void> {
try {
const location = await geolocation.getCurrentLocation();
device.position = {
latitude: location.latitude,
longitude: location.longitude
};
catch (e) {
console.error(Failed to get location. Code: {e.code}, message: {e.message});
}
private triggerAlert(device: TrackerDevice): void {
// 振动提醒
vibrator.vibrate({
duration: 1000,
count: 3
}, (err: BusinessError) => {
if (err) {
console.error(Failed to vibrate. Code: {err.code}, message: {err.message});
});
// 显示通知
notification.show({
content: ${device.name} 超出安全距离!,
title: '防丢器报警'
});
// 5分钟后再次检查
if (this.alertTimeout) {
clearTimeout(this.alertTimeout);
this.alertTimeout = setTimeout(() => {
this.checkDevicesDistance();
}, 300000) as unknown as number;
public async getTrackedDevices(): Promise<TrackerDevice[]> {
return Array.from(this.trackedDevices.values());
}
主控设备界面
// src/main/ets/pages/MasterView.ets
import { TrackerDevice } from ‘…/model/TrackerDeviceModel’;
import { BluetoothTrackerService } from ‘…/service/BluetoothTrackerService’;
import { DistributedSyncService } from ‘…/service/DistributedSyncService’;
import { bluetooth } from ‘@ohos.bluetooth’;
@Entry
@Component
struct MasterView {
@State devices: TrackerDevice[] = [];
@State scannedDevices: bluetooth.BluetoothDevice[] = [];
@State isScanning: boolean = false;
@State selectedDevice: TrackerDevice | null = null;
private trackerService = BluetoothTrackerService.getInstance();
private syncService = DistributedSyncService.getInstance();
aboutToAppear(): void {
this.syncService.subscribe(this.handleDeviceUpdate.bind(this));
this.loadTrackedDevices();
aboutToDisappear(): void {
this.syncService.unsubscribe(this.handleDeviceUpdate.bind(this));
private handleDeviceUpdate(data: TrackerDevice): void {
const index = this.devices.findIndex(d => d.deviceId === data.deviceId);
if (index >= 0) {
this.devices[index] = data;
else {
this.devices.push(data);
this.devices = […this.devices];
private async loadTrackedDevices(): Promise<void> {
const tracked = await this.trackerService.getTrackedDevices();
const synced = await this.syncService.getAllDevices();
// 合并设备列表
const allDevices = [...tracked, ...synced];
const uniqueDevices = Array.from(new Map(allDevices.map(d => [d.deviceId, d])).values());
this.devices = uniqueDevices;
private async scanForDevices(): Promise<void> {
this.isScanning = true;
try {
bluetooth.startBluetoothDiscovery();
setTimeout(() => {
bluetooth.stopBluetoothDiscovery();
this.isScanning = false;
}, 10000);
catch (e) {
console.error(Failed to scan devices. Code: {e.code}, message: {e.message});
this.isScanning = false;
}
private async connectDevice(device: bluetooth.BluetoothDevice): Promise<void> {
try {
await bluetooth.createBond(device.deviceId);
const tracker = new TrackerDevice(device.deviceId, device.name || '防丢器');
this.trackerService.startTracking(tracker);
this.selectedDevice = tracker;
catch (e) {
console.error(Failed to connect device. Code: {e.code}, message: {e.message});
}
private updateSafeDistance(distance: number): void {
if (this.selectedDevice) {
this.selectedDevice.safeDistance = distance;
this.trackerService.startTracking(this.selectedDevice);
}
private getDistanceColor(distance: number, safeDistance: number): ResourceColor {
const ratio = distance / safeDistance;
if (ratio > 1) return ‘#FF5252’; // 红色 - 超出安全距离
if (ratio > 0.7) return ‘#FF9800’; // 橙色 - 接近安全距离
return ‘#4CAF50’; // 绿色 - 安全范围内
build() {
Column() {
// 设备扫描区域
Row() {
Text('蓝牙防丢器')
.fontSize(24)
.fontWeight(FontWeight.Bold)
Button(this.isScanning ? '停止扫描' : '扫描设备')
.margin({left: 20})
.onClick(() => this.scanForDevices())
.width(‘100%’)
.justifyContent(FlexAlign.Center)
.margin({bottom: 20})
// 设备列表
List({ space: 10 }) {
ForEach(this.devices, (device) => {
ListItem() {
Column() {
Row() {
Text(device.name)
.fontSize(18)
.fontWeight(FontWeight.Bold)
if (device.isAlerting) {
Image('resources/alert.png')
.width(20)
.height(20)
.margin({left: 10})
}
Row() {
const distance = device.calculateDistance();
Text(${distance.toFixed(1)} 米)
.fontColor(this.getDistanceColor(distance, device.safeDistance))
Text(电量: ${device.batteryLevel}%)
.fontSize(14)
.margin({left: 20})
.margin({top: 5})
.width(‘100%’)
.padding(10)
.borderRadius(10)
.backgroundColor(this.selectedDevice?.deviceId === device.deviceId ? '#E3F2FD' : '#FAFAFA')
.onClick(() => {
this.selectedDevice = device;
})
})
.width(‘100%’)
.layoutWeight(1)
// 设备控制面板
if (this.selectedDevice) {
Column() {
Text(this.selectedDevice.name)
.fontSize(20)
.fontWeight(FontWeight.Bold)
Row() {
Text('安全距离:')
.fontSize(16)
Slider({
value: this.selectedDevice.safeDistance,
min: 1,
max: 50,
step: 1,
style: SliderStyle.OutSet
})
.width(150)
.margin({left: 10})
.onChange(v => this.updateSafeDistance(v))
Text(${this.selectedDevice.safeDistance} 米)
.fontSize(14)
.margin({left: 10})
.margin({top: 15})
if (this.selectedDevice.position) {
Text(最后位置: {this.selectedDevice.position.latitude.toFixed(4)}, {this.selectedDevice.position.longitude.toFixed(4)})
.fontSize(14)
.margin({top: 10})
Button(‘设为防丢目标’)
.width('100%')
.margin({top: 20})
.onClick(() => {
this.trackerService.startTracking(this.selectedDevice!);
})
.width(‘100%’)
.padding(15)
.margin({top: 10})
.borderRadius(10)
.backgroundColor('#FFFFFF')
.shadow({ radius: 5, color: '#E0E0E0', offsetX: 0, offsetY: 2 })
}
.width('100%')
.height('100%')
.padding(15)
.backgroundColor('#F5F5F5')
}
防丢器设备界面
// src/main/ets/pages/TrackerView.ets
import { DistributedSyncService } from ‘…/service/DistributedSyncService’;
import { deviceManager } from ‘@ohos.distributedDeviceManager’;
import { bluetooth } from ‘@ohos.bluetooth’;
@Entry
@Component
struct TrackerView {
@State deviceName: string = ‘蓝牙防丢器’;
@State batteryLevel: number = 100;
@State isConnected: boolean = false;
@State isAlerting: boolean = false;
private syncService = DistributedSyncService.getInstance();
aboutToAppear(): void {
deviceManager.getLocalDeviceInfo((err, info) => {
if (!err) {
this.deviceName = info.deviceName;
const device = new TrackerDevice(info.deviceId, info.deviceName);
this.syncService.syncDevice(device);
});
// 模拟电池电量变化
setInterval(() => {
this.batteryLevel = Math.max(0, this.batteryLevel - 1);
if (this.batteryLevel <= 20 && !this.isAlerting) {
this.isAlerting = true;
this.triggerLowBatteryAlert();
else if (this.batteryLevel > 20) {
this.isAlerting = false;
}, 60000); // 每分钟减少1%
private triggerLowBatteryAlert(): void {
// 防丢器自身的报警方式(如蜂鸣)
vibrator.vibrate({
duration: 200,
count: 5
});
build() {
Column() {
Text(this.deviceName)
.fontSize(24)
.fontWeight(FontWeight.Bold)
.margin({bottom: 30})
Image(this.isConnected ? 'resources/connected.png' : 'resources/disconnected.png')
.width(120)
.height(120)
.margin({bottom: 20})
if (this.isAlerting) {
Text('低电量报警!')
.fontSize(18)
.fontColor('#FF5252')
.margin({bottom: 10})
Text(电量: ${this.batteryLevel}%)
.fontSize(18)
.fontColor(this.batteryLevel <= 20 ? '#FF5252' : '#333333')
.margin({bottom: 30})
Text(this.isConnected ? '已连接至手机' : '等待连接...')
.fontSize(16)
.margin({bottom: 20})
if (!this.isConnected) {
Button('配对手机')
.width(200)
.height(50)
.onClick(() => {
bluetooth.enableBluetooth();
bluetooth.startBluetoothDiscovery();
})
}
.width('100%')
.height('100%')
.justifyContent(FlexAlign.Center)
.alignItems(HorizontalAlign.Center)
.backgroundColor('#212121')
}
四、与游戏同步技术的结合点
实时状态同步：借鉴游戏中玩家状态同步机制，实现防丢器状态的实时同步
设备发现机制：使用类似游戏大厅的设备发现方式快速配对防丢器
距离感知算法：参考游戏中玩家距离计算优化信号强度到距离的转换
多设备协同：类似游戏多设备协作，实现主从设备间的报警联动
低功耗优化：应用游戏中的移动设备功耗优化策略
五、关键特性实现
精准距离估算：
// 基于RSSI的卡尔曼滤波距离估算
private kalmanFilterRssi(rssi: number): number {
const Q = 0.1; // 过程噪声协方差
const R = 2.0; // 观测噪声协方差
if (!this.kalman) {
this.kalman = { estimate: rssi, error: 1 };
else {
// 预测
const predError = this.kalman.error + Q;
// 更新
const gain = predError / (predError + R);
this.kalman.estimate = this.kalman.estimate + gain * (rssi - this.kalman.estimate);
this.kalman.error = (1 - gain) * predError;
return this.kalman.estimate;
位置追踪优化：
// 融合蓝牙和GPS数据
private fusePosition(bluetoothPos: Position, gpsPos: Position): Position {
const alpha = 0.7; // 蓝牙数据权重
return {
latitude: alpha bluetoothPos.latitude + (1 - alpha) gpsPos.latitude,
longitude: alpha bluetoothPos.longitude + (1 - alpha) gpsPos.longitude
};
低功耗模式：
// 根据电量调整扫描频率
private adjustScanInterval(batteryLevel: number): number {
if (batteryLevel > 50) return 5000; // 5秒
if (batteryLevel > 20) return 10000; // 10秒
return 30000; // 30秒
报警策略：
// 分级报警策略
private triggerLeveledAlert(distanceRatio: number): void {
if (distanceRatio > 2) {
// 强烈报警(声音+震动)
this.fullAlert();
else if (distanceRatio > 1.5) {
// 中等报警(震动)
this.vibrationAlert();
else if (distanceRatio > 1) {
// 轻微报警(通知)
this.notificationAlert();
}
六、性能优化策略
自适应扫描间隔：
// 根据连接状态调整扫描频率
if (device.isConnected) {
this.scanInterval = 10000; // 已连接设备降低扫描频率
else {
this.scanInterval = 5000; // 未连接设备提高扫描频率
数据压缩传输：
// 压缩设备状态数据
compressDeviceData(device: TrackerDevice): Uint8Array {
const buffer = new ArrayBuffer(16);
const view = new DataView(buffer);
// 将关键数据打包到16字节
view.setUint32(0, device.lastConnected / 1000);
view.setInt16(4, device.lastRssi);
view.setUint8(6, device.batteryLevel);
// …其他字段
return new Uint8Array(buffer);
差异化设备处理：
// 根据设备类型调整功能
if (device.type === ‘tracker’) {
this.enableLowPowerMode();
else if (device.type === ‘phone’) {
this.enableFullFeatures();
后台运行优化：
// 注册后台任务
backgroundTaskManager.startBackgroundRunning({
wantAgent: wantAgent,
backgroundMode: backgroundTaskManager.BackgroundMode.LOCATION
}).then(() => {
this.startBackgroundTracking();
});
七、项目扩展方向
群体防丢网络：多用户共享设备位置信息
智能家居集成：与智能门锁联动防止钥匙丢失
历史轨迹回放：记录设备移动轨迹
AI预测提醒：基于习惯预测可能遗忘场景
AR寻物引导：通过AR箭头指引丢失物品方向
八、总结
本蓝牙防丢器应用实现了以下核心功能：
蓝牙设备间的距离实时监测
超出安全距离的多级报警系统
设备状态的分布式同步
低功耗运行模式
最后已知位置记录
通过借鉴游戏中的多设备同步技术，我们构建了一个可靠、高效的防丢系统。该项目展示了HarmonyOS分布式能力在物联网安全领域的创新应用，为开发者提供了实现蓝牙近距离感知应用的参考方案。
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